DE2844679A1 - DEVICE FOR INSPECTING THE SIDE WALLS OF BOTTLES - Google Patents

Description

-A-

Applicant: TI FORDS LIMITED of Chantry Avenue, Kempston, Bedford, MK42 7RS, England

Device for testing the side walls of

Bottles

The invention relates to a device for detecting dirt or foreign bodies, hereinafter referred to as a bottle testing device in transparent or translucent bottles or other containers, hereinafter referred to as bottles, before the bottles are filled and offered for sale, especially bottles for milk or beer that are returned after washing be used. The tester can detect dirt or debris lying on the bottom of an empty bottle; this is commonly called soil testing. With this test, however, many foreign objects, such as protrusions, Cement or paint splashes adhering to the side wall of the bottle were not found. These foreign objects or contaminants on the side walls of the bottles can only be determined by a so-called side wall test. The present invention is particularly concerned with an apparatus for sidewall testing of bottles.

Many attempts have been made to produce a machine which check the side walls of the bottles. Inflen both British patents 1,098,174 and 1,430,547 describe such machines.

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In both machines, and also in other side inspection machines on the market, the bottles must be different from the normal one Bottle conveyor removed by a star wheel and placed on a rotating tower with many parking spaces, where the fluoroscopy takes place, after which the bottles are returned to the conveyor by another star wheel. Farther each bottle must be rotated around its axis by appropriate devices during the actual test process, to ensure that the entire circumference of the bottle is scanned.

Such mechanisms for rotating the bottle are vulnerable or sensitive to damage or jamming, if a broken bottle or piece of glass enters the machine. There is such a mechanism for each station of the turret must be provided, with often 10 stations are available, the costs arising from the incidents mentioned are considerable. It is also difficult to develop a rotation mechanism that compensates for the inevitable dimensional changes, that are present in a typical bottle quantity, e.g. height differences, bottle body ovality and not vertical Bottle axes. Furthermore, due to the star wheel mechanism and the need to rotate the bottles during the test, the testing speed of these machines is limited to about 400 bottles per minute, which is insufficient to meet the requirements meet modern high-speed bottle inspection lines zni, where bottle conveying speeds of 750 bottles per

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Minute can be reached.

The object of the invention is to remedy the disadvantages mentioned. overcome and to provide a bottle inspection device in which the testing of the side walls of a bottle without bottle rotation is possible and the bottle testing speed of at least 750 bottles allowed per minute.

To achieve this object, the invention consists in a device for checking the side walls of transparent or translucent bottles for the purpose of detecting dirt or foreign bodies of a multitude of images of the side walls of a bottle to be inspected, taken from at least two different directions (in Viewed from above) is projected onto at least one integrated circuit that contains a photodiode array, wherein the photodiodes are arranged in a plurality of rows and with retrieval means for each diode along each diode row is combined to produce a video signal comprising a sequence of electrical signals corresponding to light energy, which every diode has received, in which the video signal is differentiated and in the means for leveling undesirably Signals from outside the boundaries of the bottle side walls are provided, whereby differentiated signal pulses are generated, which are representative of dirt or foreign matter in the bottle.

It has been found that it is possible to pollute

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Body anywhere on the inside surface of the side walls of a bottle can be seen by performing the test from two directions which, when viewed from above, are at right angles to each other. Both the front and the rear side wall of the bottle can be seen from either of the two test directions. However, the side check can be performed from more than two directions, if desired. . '

One feature of the invention is a mechanism for conveying of the bottles through the test station, through which the bottles that arrive substantially touching each other on the normal bottle conveyor, are accelerated so that they are a distance exhibit from each other if they are subjected to the side check, and they can then be decelerated again to the conveying speed of the bottle conveyor in order to be placed on it, where they touch each other again. This makes it easier to carry out a targeted rejection of a bottle that is. by testing as dirty or containing a foreign body! has turned out.

The invention is described in more detail below with reference to the accompanying drawings, for example. Show it:

Figure 1 is a schematic plan view of a bottle testing machine according to the invention,

Figure la shows a modified embodiment of the machine according to FIG. 1,

FIG. 2 shows a partial plan view of an alternative lens design of the optical system according to FIG. 1,

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Figure 3 is a schematic side view along a light path, which is indicated in Figure 1 with the line A-A,

FIG. 4 shows an active area of an integrated photodiode arrangement with two side by side images of the side walls of the bottle,

Figure 5 shows a gate signal for one of the diode rows or rows the diode arrangement,

Figure 6 is a block diagram.

FIG. 1 shows a general plan view of a machine with bottles 1a, Ib ... 1k, which pass a test station 2, in a straight line Line according to the arrow, the bottles being supported from below by a bottle conveyor 3.

At the access end of the machine there is a screw conveyor 4 driven by a motor and variable speed device (not shown) is driven at a rate corresponding to the number of bottles per minute that are on the main bottle conveyor be treated. This device is arranged at the beginning end of the screw, while the terminal end of the screw is in a bearing 5 is located.

The pitch of the screw increases in the longitudinal direction of the screw, namely gradually increasing from one, which is the bottle diameter at the beginning of the screw corresponds to up to 1.5 times

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the bottle diameter at the discharge end of the screw. This will be the bottles reaching the screw 4 from the main conveyor and touch each other, gently accelerating as they pass the snail, 'and point one at the discharge end of the snail Distance from each other, which corresponds to 1.5 times the bottle diameter.

The bottle conveyor 3 is driven by the screw 4 or by a second drive with a variable conveying speed (not shown), which makes it possible to adjust the conveying speed of the bottle speed at which the bottles Leave screw 4, regardless of the setting of the first variable speed device, which the Bottle throughput determined by the machine. This arrangement ensures that the distance between the exiting bottles is maintained if these are conveyed through the test station 2, they are only supported on their bottoms, which are on the conveyor 3 rest. During this movement, the bottles again pass the test station, which is described below, and after the Test they are detected by a second screw conveyor 7, which is supported at its starting end by a bearing 8 and is driven at its final end by the first screw conveyor 4. The drive (not shown) is preferably such that the time behavior can be adjusted so that the entry into the first conveyor niche of the second screw 7 is at the correct one Place lies around bottles without changing their position

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to capture the conveyor 3. The amplitude of the screw 7 at its starting end is conical in order to do the work just mentioned to facilitate. Bottle guide rails 9a and 9b hold the bottles in the helix of the screws 4 and 7 during their Passage.

Another purpose of this second screw is to protect the test zone from the effects of any back pressure of the conveyed Keep bottles clear. The auger also provides a convenient location for a bottle reject mechanism. Such is described, for example, in patent application P 28 12 063.0, with the prerequisite that the Bottle is in a predetermined position downstream of the test station.

The method according to the invention for obtaining a complete inspection of the side walls of a bottle without rotating them is based on the fact that it has been found possible to see dirt and foreign bodies at any point on the inner surface of the bottle body from two directions ( viewed in plan), these directions essentially enclosing an angle of 90 degrees. Both the front and the behind it bottles surface (inner surfaces) may result from these two directions being seen.

According to this feature, according to the exemplary embodiment

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Figure T the bottle 1 £ in the center 6 of the test station 2 of two Directions which are at right angles to each other illuminated by the lamps 10a and 10b, the lamps being made of tungsten incandescent lamps, Fluorescent ^ discharge lamps, xenon flash or xenon discharge tubes or other light sources that suitable for the color and / or density of the bottles. Light scattering screens 1 1 can be provided in front of the corresponding lamps be.

A lens 12 produces two images of the bottle sides, as they are seen from the two directions 13 and 14, these Directions include a right angle. Two mirrors 15 and 16 and two further mirrors 17 and 18 allow the individual Lens 12 to produce two side-by-side images and these an integrated circuit 19 containing a photodiode array, the diodes in a plurality of rows arranged and combined with means for interrogating each diode one after the other and row by row. A suitable built-in Circuit arrangement of this type has 64 rows with 64 photodiodes each and is known as "2DI 64 X 64 matrix array". This arrangement is supported by the Integrated Photomatrix Limited of Dorchester, England.

A partition plate 20 in the frame distance of the lens prevents external light from outside the left image causes degradation or deterioration of the right image, and vice versa.

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An alternative optical design is shown in FIG. Here, separate lenses 21a and 21b are used for each viewing direction, and a mirror 22 with a 90 degree silver mirror surface The two images are reflected in the image distance between the two lenses, the two in the form of rays of light Project side-by-side bottle images onto the device from the photodiodes, as already mentioned.

Figure 3 is a side view along the viewing path A-A, in which the bottle If in the center 6 of the test station is on the conveyor 3. However, this illustration shows only one of the two viewing directions, with the mirrors 16 and 18 are omitted for clarity. The light diffuser 11 illuminates the bottle 1f, and the rays of light are passed through the lens 12 is collected and at a focal point of the photodiode array 19 directed. The lens 12 is arranged at a level which is close to the plane on which the bottle stands, so that the front and rear sides of the lower portion of the bottle body are unobstructed by the bottle bottom or the sponsor can be viewed.

Figure 4 shows the active area of the photodiode array 19 with two images 24 and 25, which are side by side, with one Image & inen dirt body 23, which is in one of the two Viewing directions is visible.

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The diode array is scanned horizontally line by line or row by row and produces a video signal, its Amplitude proportional to the light energy at any moment this energy being integrated over a period between successive samples and that of the diode was received, which at that moment was just being scanned became.

The diode arrangement 19 is continuously scanned and that Video output signal is processed by a signal in a gate element, which signal is from one or more sensors is derived, which are arranged and switched to determine a bottle in the test station. The length of time this gate signal must be long enough for the entire row of diodes to be scanned. With this array of diodes, there are scans from 800 to 1000 diode test fields per second possible, from which it follows that the gate processing time must be a minimum of about 1.25 milliseconds. During this time, a typical beverage bottle will move through the machine at a conveyor speed of 750 bottles per minute, have covered a distance of about one millimeter while it is being checked, and thus blurred parts of the image due to bottle movement will be negligible.

The video signal derived from the bottle while the bottle is in the inspection station is differentiated by one

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Contain momentum that has a rapid transition from light to dark or vice versa along each of the scanned rows of diodes. Such impulses show the presence of foreign objects and are used to actuate a bottle reject mechanism at a desired time.

Figure 4 shows in detail the surface of the photodiode array, to which the two bottle pictures 24 and 25, as they are in the two directions, which are at right angles to each other, can be seen, focused and on which these images are side by side for simultaneous scanning by the arrangement 19 appear. The areas of interest, which together cover essentially the entire surface of the bottle body, are outlined by the boundary lines 26 and 27. One programmable read-only memory (PROM) is programmed to hold another Provide goal video signal which is used to accept reject signals from those two, through the boundary lines 26 and 27 to be derived from certain areas, and to ignore other signals from the rest of the arrangement 19. For example it is necessary for the PROM, for the line number twenty of the arrangement 19, which line starts with 28 in FIG. 4 numbered is to control the video signal for this line in the "on" state with a gate pulse after the twelfth diode has been reached, then turn "off" again after the twentieth diode has been reached, then turn "on" again after the 44 # diode has been reached, and finally "off" again

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switch after the 52 _C diode has been reached. These points are indicated by 29, 30, 31 and 32, respectively, and the gate signals of this line are shown in FIG.

A circuit 50 for differentiating the video output signal, for driving out unwanted signals from areas of no interest and effecting other operations like it is described above, is basically constructed as described in German patent application P 28 34 581 and is shown in FIG. 6 thereof. As shown in Figure 6 of the present application, the photodiode array is voltage 19 is scanned by a row scanner 51 to generate a video signal. This video signal becomes a differentiator 52, the output signal of which is fed to a gate 53. The clock pulses of the row scanner 51, which is used to retrieve the Series arrangement is used, diode by diode along a diode row and diode row by diode row over the entire Area of the test field of the arrangement are used to be entered into the programmable memory 54 (PROM) to be able to. This memory is programmed to generate a gate pulse with the correct ON-OFF period for each row of diodes, as explained above. These gate impulses control the function of the gate 53 / so that only the impulses that are differentiated on 'Video output remain, those are who the foreign objects

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or match the dirt in the bottle. ■

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The memory can be programmed to make an area similar Define the form within which the desired signals can occur and outside which the irrelevant or unwanted Signals must be rejected or suppressed.

A large foreign body with straight edges that are parallel to the scanned rows of diodes is not detected because it darkens all active diodes in & er series and, accordingly, there is no change in the lighting along this series takes place, the differentiated output signal is zero would be. To overcome this problem, a reject signal is also derived from the video signal that covers the entire test field includes and which before differentiating and gating consists of 64 series signals. This signal is fed to an amplifier 55 with a limited high frequency response, so that the output signal can be quickly changed or Changes that occur between each series signal cannot follow, and this results in a smoothed one for each test field Output signal r

The two unwanted signals at the beginning and end of each test field can be controlled with a pulse that is generated in the memory 54 (PROM). This pulse is finally fed to a gate circuit 57 so that only the desired signal remains and, together with pulses of the series signals due to foreign objects, are used to form a rejection pulse

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to an ejecting circuit 58 / the one with a mechanism cooperates as it is in the German patent application P 28 12 063.0 is described to eject a dirty bottle from the bottle conveyor. The two differentiators 52 and 56, one being responsible for the row signals and the other being responsible for the complete test field signal (s) of any polarity, which depends on whether the lighting changes from light to dark or vice versa. At a small objects or foreign bodies will generally have both polarities present. In the case of a large foreign body, for example half of the bottle bottom is darkened, it may be that only signals of one polarity are generated, which depends on the scanning direction over the edge of the foreign body.

At some stages of signal processing it is useful to reverse the signals of one polarity so that only signals are the same Polarity are present. The differentiated signals obtained from foreign objects in the bottle are pulses . of approximately triangular shape, but variable in the Amplitude and duration, whatever the size and opacity of the foreign body detected. A very small body that only obscures one diode in a row of diodes becomes be of small amplitude and short duration compared to a body that obscures about 10 consecutive diodes.

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The differentiated signals can be used to drive a Schmitt trigger that makes an output pulse more constant Amplitude for a period of time during which the input signal is above a set response value. This can be on one be set low so that even the signal from a single, darkened diode is an output from the trigger is given. "

Separate Schmitt triggers 60a, 60b can be used for positive and negative Polarity parts of the signal which is amplified in a differential amplifier 59 are used. The resulting impulses of the same polarity are combined in an OR gate 61.

The resulting pulse forms the input signal into a monostable Circle 62 and also to a NAND gate 63. The monostable Circuit 62 has the task of giving an output pulse of constant amplitude and duration for each input pulse, the Duration by changing the time constant of the resistance-capacitance coupling components is adjustable. The output from monostable circuit 62 sees a second input to that NAND gate 63 in front.

The NAND gate 63 will now only give an output pulse if the duration of the input pulses exceeds the set pulse length of the monostable circuit 62. Therefore, this circuit operates as a pulse width comparator, and, by adjusting the time constant of the monostable circuit 62, all of the pulses of shorter duration than the set pulse length can be excluded from the NAND gate output, wherein the output signal

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this gate is passed to the ejector circuit 56.

Thus, small "foreign bodies that darken a diode can be detected or neglected by the appropriate Setting the time constant of the monostable circuit. A constant, fake signal can also be caused by failure a diode in the diode array can be ignored. This array also gives a measure of the immunity of Glitches of very short duration caused by the earlier-parts of the circle may have been included.

In the case of a practical bottle testing device, it is necessary to that it is possible to adjust the sensitivity to different sized bodies or objects in order to reject To avoid too many cleaner bottles with minor defects such as glass stains or bubbles or to reject them Bottles on a conveyor avoid those on the outside surface have oil foam or the like.

With the system described, the sensitivity can be as described can be changed or by setting the time constant the differentiator or by changing the response value at which the Schmitt trigger works.

The diode array is continuously scanned and

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supplies the video signal, which is processed in the manner described will. An AND gate 64 is also provided, which is operated by a bottle detection sensor 65, so that rejection signals, if available, can only be obtained if there is a bottle in the. Test station is located.

The sensor 65 is designed to detect a bottle movement of Allow 1 to 2 mm before the exit gate 64 is turned off. Only rejection signals received during this time reach the ejector circuit 58.

One method of sensing bottle position is to use a radiation source 65 to generate two ors three closely spaced beams of infrared or visible light arranged to pass through the bottle opening or the bottle head are interrupted when the bottle passes the test station. The distance between the two outer ones Rays in relation to the bottle head diameter determine the distance at which the bottles travel during the test. the Phototransistors (only one shown at 66) that receive the two or three beams generate signals that logic devices 67, which perform other functions and also the gate control of the signals to the rejection device effect, e.g. they can be used to determine the bottle head diameter to be measured or determined so that oversized or undersized bottles can be rejected.

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Furthermore, a logic element can be provided so that the test is only initiated when the bottle is in the correct position Direction the rays happened. This avoids problems caused by backward movement of the bottle over a short distance caused.

Other detection systems can be used with the test system described here be united and their corresponding rejection signals can be entered into this system so that the same Rejection mechanism can be used for multiple reasons for rejection. For example, a sensor can be provided to Determine water in a bottle to be examined. A detector 68 for dark bottles can also be provided, controlled by the video signal or by a separate single phototransistor to cover the entire floor area To look through the bottle opening to see a bottle with a totally darkened bottom or with one stuck in the neck of the bottle Reject corks. The output signal from the detector 68 can be sent to the OR gate 69 along with the output signals from the NAND gate 63 and from gate 57 are fed.

In an alternative embodiment, the output signal from gate 57 can be fed to differential amplifier 59.

FIG. 1a shows a modification of the outlet end of the device according to FIG. 1, in which the screw conveyor 7 is replaced by an endless conveyor 7a, which consists of articulated blocks with semi-cylindrical side parts that grasp and convey the bottles.

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Claims (8)

Patent Attorneys Dc Hugo Wilcken Dipl.-lng. Thomas Wilcken Dipl.-Chem. Dr. Wolfgang Läufer Musterbahn 1 _ - _ 240O Lübeck 1 Applicant: TI FORDS LIMITED of Chantry Avenue, Kempston, Bedford, MK42 7RS, England Patent claims 1. ) Device for testing the side walls of transparent or translucent bottles for the purpose of determining dirt or foreign bodies, characterized in that a plurality of images of the side walls of a bottle to be tested, which is viewed from at least two different directions (seen in plan) on projecting at least one integrated circuit including a photodiode array in which the photodiodes are arranged in a plurality of rows and combined with retrieval means for each diode along each diode row to produce a video signal comprising a sequence of electrical signals representative of light energy which each diode has received that the video signal is differentiated. and that means are provided for modulating undesired signals from outside the boundaries of the bottle side walls, whereby differentiated signal pulses are generated which are representative of dirt or foreign bodies in the bottle. 2. device.after. Claim 1 with a mechanism for conveying of the bottles through a test station where the side walls of a bottle are tested, characterized in that · that the mechanism the successive bottles, which, in the ORIGINAL INSPSCTCD 909817/0737 essential to arrive touching each other on the conveyor - accelerated so that they are spaced apart when they reach the test station. 3. Apparatus according to claim 2, characterized by a delay mechanism, which delays the bottles when they leave the test station and feeds them to the bottle conveyor with its conveying speed, the bottles essentially touching each other again. 4. Apparatus according to claim 1, 2 or 3, characterized by lighting means for illuminating the side walls of a bottle, while this moves with a substantially vertical axis through the test station, the lighting from two directions takes place, which are substantially at right angles to each other (seen in plan view), and by optical means which are substantially are arranged in the plane in which the bottom of the bottle is located, the optical means having two images of the illuminated Generate side walls in said directions and the images on the at least one integrated circuit project. 5. Apparatus according to claim 4, characterized in that the optical means project the images side by side onto a single integrated circuit. 909817/0737 6. Device according to one of claims 1-5, characterized by means for reversing the differentiated Signal pulses of one polarity, so that all signal pulses have the same polarity. 7. Apparatus according to claim 6, characterized by a device to convert the differentiated signal pulses from constant amplitude with a duration which corresponds to the period of time within which the differentiated amplitude pulses are above a set response value. 8. Apparatus according to claim 7, characterized by a device to change the set response value. §09817 / 0737